Self-expanding, pseudo-braided intravascular device

ABSTRACT

A self-expanding, pseudo-braided device embodying a high expansion ratio and flexibility as well as comformability and improved radial force. The pseudo-braided device is particularly suited for advancement through and deployment within highly tortuous and very distal vasculature. Various forms of the pseudo-braided device are adapted for the repair of aneurysms and stenoses as well as for use in thrombectomies and embolic protection therapy.

BACKGROUND OF THE INVENTION

The present invention relates to self-expanding, knitted devices andmore particularly, to a self-expanding knitted device for intravascularrepair of distal and tortuous vasculature.

The vasculature of an animal or a human characteristically suffers froma variety of maladies. Vessel walls can weaken and become distended overtime in response to blood flow and pressures, thereby resulting information of aneurysms. Such aneurysms can take on a myriad of forms. Inparticular, aneurysms may form at or near bifurcated vessels creatingenlarged areas about the bifurcation, or may form a pocket, for example,in side walls of vessels. Due to the complications associated withaneurysms that rupture or otherwise fail, it is critical that ananeurysm be treated expeditiously and effectively. Intravasculartreatment procedures include placing grafts within the aneurysm in amanner to ensure that blood flows through the graft rather than throughthe weakened vessel. Additionally, in the event that the aneurysm is inthe form of a pocket in the side wall of a vessel, a stent might firstbe placed at the repair site then the pocket filled with material suchas coils.

Stenoses also typically form in vasculature of humans and animals.Specifically, thrombotic or atherotic stenoses can form nearly anywherein the vasculature. Such narrowing of the vessel is, of course, highlydangerous to the patient where the afflicted vessel provides the soleblood flow access to critical parts of the body. To treat such stenoses,a supporting structure can be placed at the diseased site for thepurpose of enlarging and holding open the vessel. It is known in the artto employ stents for this purpose.

Vessel occlusions can also be treated by employing devices which areactuated to debulk and remove vessel occluding thrombi. This procedureis generally referred to as a thrombectomy. Typically, such devices areintravascularly advanced to the repair site and manipulated to removethe unwanted material from the vessel by physically engaging thethrombus and severing the same from the vessel wall.

Due to procedures such as thrombectomies or due to the natural, albeitundesirable, function of a patient's vasculature, emboli may be foundtraveling through a blood vessel. Embolic material can cause unwantedblockages or otherwise facilitate the formation of an occlusion in avessel which too, can be highly dangerous to a patient. To address thisproblem, emboli-catching filters can be intravascularly placed withinvasculature to thereby provide embolic protection. Such devices areoften implanted temporarily within vasculature and removed upon beingsatisfied that the undesirable embolic material has been captured.

In certain situations, it is desirable to aid the formation of thrombus.For example, devices may be placed within aneurysmal spaces to slow andeventually cease blood flow therethrough. This procedure is sometimesreferred to as embolic therapy, the basic thrust of which is to minimizeor eliminate exposure of weakened sections of vasculature to blood flowand pressure.

Unfortunately, many areas of vasculature are inaccessible by aconventional intravascular repair means because the repair devicestypically employed are often too large or rigid to be effectivelyadvanced through tortuous vasculature or to vasculature that is verydistal to the site through which the vasculature is accessed.Alternatively, in the event that there is success in advancing therepair devices to the diseased portion or repair site of thevasculature, conventional repair devices sometimes lack a large enoughexpansion ratio and/or radial stiffness to accomplish the necessaryrepair. Moreover, conventional devices can lack a profile suited toavoid traumatic engagement with a vessel wall or sufficient radiopacityso that remote observation is impossible.

Thus, where an intravascular approach is not available to the physician,invasive surgical techniques must be applied. To wit, a patient's chest,abdomen or cranium, for example, must be directly traversed in a majorsurgical procedure.

Hence, those concerned with repair of diseased vasculature haverecognized the need for devices that can be employed to effectivelyrepair distal and highly tortuous vasculature. The present inventionfulfills these needs.

SUMMARY OF THE INVENTION

Briefly, and in general terms, the present invention provides devicescontemplated for the repair of highly tortuous and distal vasculature.Basically, the invention is directed to a self-expanding, pseudo-braidedstructure that is characterized by having a large expansion ratio andhigh flexibility as well as an improved radial strength accomplishedthrough the advantageous utilization of deflection energy.

In one preferred embodiment, the devices of the present invention arefabricated from a single filament configured into a repeating helicalpattern that is interlaced into a mesh or pseudo-braided tubular shape.The filament may embody an elongate highly elastic and shape settablematerial. A reversal of direction that the filament undergoes presents ablunt, rounded surface that is atraumatic to vessel walls. The structurein the present application is referred to as pseudo-braided. Braiding isthe interlacing of at least three wires at various angles to each otherto form a braid, whereas the present invention uses a single filamentthat is interlaced with itself along the length of the structure atvarious angles. It is within the scope of the invention to interlaceanother filament or a plurality of other filaments into the pseudo-braidformed by the single filament.

In another aspect of the invention, the pseudo-braided or interlacedstructure has a high expansion ratio with a low metal to space ratio. Alarge expansion ratio is accomplished by the unique single filamentconstruction that provides additional springback forces.

In other aspects of the invention, there are various methods forterminating the filaments. Additionally, various methods arecontemplated for adjusting the radiopacity as well as the expansion andspring characteristics of the pseudo-braided devices. Various methodsare also contemplated for improving coverage of the pseudo-braideddevices and enhancing the anchoring of the same within distal andtortuous vasculature.

The self-expanding, pseudo-braided devices disclosed are intended foruse in addressing various maladies effecting vasculature. In particular,the self-expanding, pseudo-braided devices can be configuredspecifically to facilitate the repair of aneurysms and stenoses as wellas to act as filter or thrombectomy devices.

These and other objects and advantages of the invention will becomeapparent from the following more detailed description, when taken inconjunction with the accompanying drawings of illustrative embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a pseudo-braided device of the presentinvention;

FIG. 2 is an end view of the pseudo-braided device shown in FIG. 1;

FIG. 3 is a side view of a pseudo-braided device of the presentinvention, depicting a device with a flared end;

FIG. 4 depicts a first embodiment of a filament reversal;

FIG. 5 depicts a second embodiment of a filament reversal;

FIG. 6 depicts a third embodiment of a filament reversal;

FIG. 7 depicts a fourth embodiment of a filament reversal;

FIG. 8 depicts a fifth embodiment of a filament reversal;

FIG. 9 depicts a first embodiment of a method for joining ends of afilament;

FIG. 10 depicts a second embodiment of a method for joining ends of afilament;

FIG. 11 depicts a third embodiment of a method for joining ends of afilament;

FIG. 12 depicts a fourth embodiment of a method for joining ends of afilament;

FIG. 13 depicts a fifth embodiment of a method for joining ends of afilament;

FIG. 14 depicts a sixth embodiment of a method for joining ends of afilament;

FIG. 15 depicts a seventh embodiment of a method for joining ends of afilament;

FIG. 16 depicts a eighth embodiment of a method for joining ends of afilament;

FIG. 17 is a perspective view of a first alternative method of forming apseudo-braided device of the present invention;

FIG. 18 is a perspective view of a second alternative method of forminga pseudo-braided device of the present invention;

FIG. 19 is a side view of a sectioned portion of a blood vesselsuffering from an aneurysm and a pseudo-braided device of the presentinvention being deployed from a catheter;

FIG. 20 depicts the implantation of the device of FIG. 19 within avessel;

FIG. 21 is a side view of a sectioned portion of a blood vesselsuffering from an aneurysm and a pseudo-braided device of the presentinvention being deployed from an alternative embodiment of a deliverycatheter;

FIG. 22 is a side view of a sectioned portion of a blood vesselsuffering from a stenosis and a pseudo-braided device of the presentinvention being deployed from a catheter;

FIG. 23 depicts the implantation of the pseudo-braided device of FIG. 22within a vessel;

FIG. 24 is a side view of a pseudo-braided device of the presentinvention configured as an embolic protection device;

FIG. 25 depicts a side view of an alternate embodiment of thepseudo-braided device of the present invention configured as an embolicprotection device;

FIG. 26 is a side view of a pseudo-braided device of the presentinvention configured as a thrombectomy device;

FIG. 27 depicts a side view of an alternate embodiment of thepseudo-braided device of the present invention configured as athrombectomy device;

FIG. 28 depicts a side view of yet another embodiment of thepseudo-braided device of the present invention configured as athrombectomy device; and

FIG. 29 is a side view of a sectional portion of a portion of a bloodvessel suffering from an aneurysm and a pseudo-braided device of thepresent invention configured to be placed within the aneurysm.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning now to the drawings, and particularly to FIGS. 1 and 2, there isshown a self-expanding pseudo-braided structure 50 of the presentinvention. The pseudo-braided device 50 is contemplated for use inhighly tortuous and very distal vasculature of an animal or human. Dueto its novel structure, the pseudo-braided device 50 is flexible in acompressed configuration and conformable to tortuous anatomy in arelaxed condition. Moreover, the device embodies high flexibility and alarge expansion capability while providing sufficient radial force(i.e., hoop stiffness).

In a presently preferred embodiment, the pseudo-braided device 50 of thepresent invention is formed from the single filament 52. The filament 52is configured into a repeating helical pattern that is interlaced uponitself by passing the end of the filament over then under the filamentforming the helix as the end of the filament is wound down and back upthe length of the structure to thereby form a generally tubular body 54.At the crossings of the filament there can be local deformations formedas the top wire is bent over the bottom wire however it has beendiscovered that for most applications deformations are not necessary toadd spring force and resistance against fraying because of the endsformed by the reversal of winding. The tubular body 54 defines aninterior lumen 56 and includes a first end 58 and second end 60.

It is also contemplated that the self-expanding pseudo-braided structurecan embody modified tubular configurations. That is, as shown in FIG. 3,one end of the self-expanding pseudo-braided structure 50 can include anincreased diameter section or flare 61. Alternatively, both ends of thedevice can include a flare 61, such flares can have the same generalshape or one flare may be greater than the other.

The filament 52 is preferably an elongate, highly elastic and shapesettable member. In one preferred embodiment, the filament 52 has acircular cross-sectional profile and can comprise nickel titanium alloy,eligiloy™, steel or other suitable materials.

In order to assemble the pseudo-braided device 50, it is contemplatedthat the filament 52 can be wrapped about a mandrel in a first directionand in a helical fashion for a desired length along the mandrel (notshown). Once the desired length is achieved, the direction of winding isreversed.

Reversal of winding can be accomplished in a number of ways. It iscontemplated, however, that the reversal of winding present a smooth,blunt surface that would be atraumatic to a vessel wall. As shown inFIG. 4, such an atraumatic reversal can be accomplished employing asimple arc 62. Atraumatic reversal can also be provided by single 64 ordouble 66 loop backs as well as a figure-8 reversal 68 or a full-turnhelical reversal 69 as shown in FIGS. 5-8, respectively.

Various radii of curvature and length of loops can be employed accordingto the application. The loops or hoops of the various reversalscontemplated can have a constant or irregular radii of curvature and theloops can have an acute radius of curvature (not shown). It is believedthat minimizing stress concentrations in the reversals may have theadded benefit of optimizing springback forces. Thus, stressconcentration in the reversals can also be varied for a particularapplication. Moreover, in order to facilitate the reversal of directionof the filament 52, the mandrel can have pegs extending therefrom atdesired intervals, about which the filament can be routed.

Once a reversal direction is made, the filament is interlaced in anover/under fashion about itself in a helical pattern in the reverseaxial direction but same rotational direction. The desired density ofthe wall 70 defining the tubular body 54 is accomplished by altering thenumber of reversals and the longitudinal spacing 72 of adjacent memberswrapped in the helical pattern. That is, the number of traversals, whichis defined as the portion of the filament 52 between two reversals ofdirection, can be varied as can the number of revolutions per traversal.Typically, the number of reversals at each end 58, 60 of the tubularbody 70 number from six (6) to twelve (12) and as much as twenty (20).

Upon achieving a desired pseudo-braided pattern and wall density, theends 74, 76 of the filament 52 are joined. There are a myriad of ways inwhich the ends 74, 76 can be joined. While the figures illustrate suchjoining as occurring generally at the middle of the pseudo-braideddevice 50, it is also contemplated that such joining can occur at theends of the structure or anywhere in between. Ultimately, however, it isdesired that the joining of the ends 74, 76 of the filament 52 beaccomplished in a manner such that the vessel wall is presented with asatraumatic a surface as necessary for a particular application, there isa low profile, and no compromise in device function.

As shown in FIGS. 9 and 10, one way of joining the end 74, 76 of thefilament 52 is to twine them together. The ends 74, 76 of the filamentcan also be joined by soldering or welding to form a welded joint 78 asshown in FIG. 11. A preferred method of welding is laser welding.

Alternatively, the ends 74, 76 of the filament 52 can be joinedutilizing potted tantalum powder 80, as depicted in FIG. 12. In order todo so, the tantalum powder is first mixed with an epoxy. Thereafter, thefilament 50 is coated with the tantalum/epoxy compound and left to cure.

Moreover, the ends 74, 76 of the filament 52 can be configured into alinear slide arrangement 82 (see FIG. 13). In such an arrangement, onefilament end 74 is wrapped around the other filament end 76 whichremains straight or undeformed. This means for joining the end 74, 76 ofthe filaments 52 has the advantage of compensating for lengthmismatches. To wit, one wire can move relative to the other.

The ends 74, 76 of the filament can also be formed with flattenedwelding surfaces 84 (FIG. 14). These weld surfaces 84 are then alignedand thereafter welded together by conventional methods.

Finally, the ends 74, 76 of the filament 52 can be crimped togetherusing a sleeve 86 or are otherwise joined by way of a ball member 88(FIGS. 15 and 16). In both instances, a bore is provided to receive bothends 74, 76 of the filament 52. In the case of the sleeve 86 embodiment,the outer surface of the sleeve 86 can be crimped to retain the sleeve86 on the ends 74, 76 of the filament 52. A press fit is contemplatedfor the ball 88 and configuration.

The assembled pseudo-braided device 50 embodies a number of uniquefeatures. In particular, the reversal of the knit direction provides aresilient response at the ends 58, 60 of the pseudo-braided device 50compared to that of other conventional braided structures that haveunconnected wire ends. That is, reversals of direction act as a springand tend to attempt to return to pseudo-braided device to its originalexpanded shape. This feature allows the pseudo-braided device 50 to becompressed to smaller than ten (10) percent of its original diameter andonce released, to spring back to its original uncompressedconfiguration. Accordingly, the pseudo-braided device 50 of the presentinvention is characterized by having a very large expansion ratio.

Embodying a very large expansion ratio provides the pseudo-braideddevice 50 of the present invention with a number of advantages. Inparticular, the pseudo-braided device 50 can be delivered withinvasculature using very small diameter catheters or microcatheters. Thisin turn allows for the placement of the pseudo-braided device 50 withinvery distal vasculature. Thus, using microcatheters to deliver thepseudo-braided device 50 facilitates advancement through highly tortuousas well as very narrow vessels such as in the cerebral vasculature.

Furthermore, the reversals of direction of the filament 50 tend toimprove radial force (i.e., hoop stiffness) by forcing deflection energyto bend the reversal arc as well as displace the same. With particularreference to FIG. 4, reversals defined by simple bends 62 embodyrelatively high stress concentrations at the bend 62. Such high stressconcentrations may be suitable for a purpose requiring a particulardeflection energy. In contrast, reversals defined by full-turn helixes(FIG. 8), for example, tend to distribute stress concentrationsthroughout the helix 69 and therefore provide a different deflectionenergy. By comparison, braided devices that lack reversals deflect inresponse to a load much more readily than the ends 58, 60 of thepseudo-braided device of the present invention and those braided devicesonly rely on pivots at the crossings of the wires whereas the presentinvention embodies crossings plus spring ends.

The crossing angle 90 can also be varied for a particular application.The crossing angle 90 is defined by two portions of the filament thatcross each other. It is presently contemplated that the crossing anglecan range up to approximately 90 degrees or more. It has been found thatthe braid angle directly affects radial stiffness and conformabilitywhich can thus be optimized for a particular application.

It has also been recognized that joining the ends 74, 76 of the filamentmaintains filament alignment. Filament alignment is importantparticularly when deploying the pseudo-braided device 50 in extremelytortuous vessels for a number of reasons. First, in the event thefilaments 52 were permitted to slide out of place, weaker areas would becreated in the pseudo-braided device 50. Those weaker areas would havean increased propensity to buckle. Secondly, if filaments 52 were toslide out of place, the mesh openings can become variable. As a result,there would be larger openings in the mesh or interlaced structure insome places that would reduce functionality of the device. Finally, iffilaments were permitted to slide out of place, catheter distortionduring deployment will likely increase. Thus, when the filaments 52 ofthe pseudo-braided device maintain good alignment while in thecompressed condition, the individual radial forces of each filament 52add together to form a consistent radial force in all directions alongthe length of the pseudo-braided device 50.

It is also possible to produce a pseudo-braided device 50 that iscomprised of one wire, where that one wire has variations along itslength that corresponds to specific pseudo-braiding processes of aparticular desired configuration. To wit, a wire could be masked andchemically etched to produce a variable diameter wire that correspondsto the pseudo-braided device 50 design of choice, such that for example,the bends of the filament 52 that comprise the ends of thepseudo-braided device 50 can be of a smaller diameter than the wire thatcomprises the remainder of the pseudo-braided device body 70.Additionally, the bends could be of a larger diameter for providing agreater expansion rate and radial force. These variations mayadvantageously create a pseudo-braided device 50 with a desiredstrength, without increasing its resistance to being pushed through acatheter lumen in a compressed configuration.

This kind of design variation could be followed for other attributes aswell. For example, such as for non-thrombogenic coatings, coatings lacedwith therapeutic drugs, plating processes to selectively increaseradiopacity, and plating processes to selectively increase stiffness.

Alternatively, rather than a round profile, the filament 52 can beformed from a filament having various other cross-sectional profiles.That is, the filament can comprise an oval, triangular, rectangular,square, bowed, crescent moon, or tapered profiles. The filament 52itself can also be formed from a small diameter tube or be configuredinto a coil along its length.

It is also recognized that the desired pseudo-braided structure can bemade from a plurality of filaments 52. Such plurality of filaments 52can be configured with a number of reversals of varying types, so thatthe benefits associated therewith can be used advantageously. The endsof these filaments can also be joined together to provide atraumaticengagement with vessel walls as discussed above.

When deploying the pseudo-braided device 50 of the present inventionwithin a patient's vasculature, it is desirable to be able to remotelyobserve the placement thereof. Thus, it is important that thepseudo-braided device 50 be sufficiently radiopaque so that such remoteobservation is possible by conventional methods such as fluoroscopy.

Referring now to FIGS. 15 and 16, the radiopacity of the pseudo-braideddevice 50 can be enhanced by employing platinum or other sufficientlyradiopaque materials as the crimping sleeve 86 or the ball end 88.Platinum coils (not shown) could similarly be wrapped about portions ofthe filament 52 to act as radiopaque markers. Additionally, the filament52 can be twined with one or more platinum filaments along its length,thereby providing a pseudo-braided device 50 that is radiopaque from oneend to the other.

Additionally, it is contemplated that in certain applications, it may bedesirable to plate the filament with gold or platinum. The entirety ofthe tubular body 70 can be plated or the reversals could be masked andthe remainder of the body 70 be plated. By thus masking the reversals,the desirable spring characteristics of the pseudo-braided device 50 ofthe present invention can be preserved.

Referring now to FIGS. 17 and 18, there is shown methods ofmanufacturing the pseudo-braided device 50 of the present invention in amanner to optimize vessel coverage for particular applications. As shownin FIG. 17, a particular configuration of the pseudo-braided device 50can be formed by wrapping a filament 52 about a forming mandrel 92 suchthat there is tight winding at an inferior end portion 94 and relativelylooser winding at a superior end portion 96. The tightly wound portionbeing contemplated to provide the resultant pseudo-braided device 50with structure for anchoring and for increasing surface area for vesselcoverage. The more loosely wound portion provides a gradual transitionto the more tightly wound portion as well as a means for more easilydeploying the pseudo-braided device 50 when it is released from acatheter.

FIG. 18 additionally depicts a wavy midsection 98 which is contemplatedfor use in also increasing coverage when the pseudo-braided device isdeployed within a vessel. The waves can generally resemble a sinusoidalpath and can also take on an undulating serpentine pattern. Such waves98 can alternatively extend the length of the filament thereby providingthe pseudo-braided device with increased coverage throughout its length.Such waveforms are created by threading the filament through a meshsetting shape then again wrapping the filament about a mandrel againsetting the shape.

It has also been recognized that the waveforms like those shown in FIG.18 can be spanned with a highly elastic material for the purpose ofagain improving coverage. As with the closely wound filament embodiment,the waves can additionally improve anchoring capabilities by enhancingin a circumferential direction, the traction between the vessel wall andthe pseudo-braided device 50.

The pseudo-braided device 50 of the present invention has applicationsin a number of areas including operating as an aneurysm cover, inconjunction with thrombotic and artherotic stenosis therapy, as anembolic protector, as a thrombectomy device and in embolic therapy. Asstated, due to its high expansion ratio and superior flexibility, thepseudo-braided device 50 can be placed within vasculature and advanceddeep within the patient's anatomy to a repair site. Once there, thepseudo-braided device 50 can be deployed within highly tortuous vascularfor the purpose of addressing the particular malady effecting thevessel. As shown in FIGS. 19 and 20, the pseudo-braided device 50 of thepresent invention can be advanced within a blood vessel 100 using adelivery catheter 102. Due to the ability to reduce the pseudo-braideddevice 50 to less than 10 percent of the expanded diameter,microcatheters can be utilized for this purpose. In a preferredembodiment, the delivery catheter is contemplated to include orcooperate with a pusher 103 that operates to facilitate relativemovement between the pseudo-braided device 50 and the delivery catheter102.

In an alternate configuration (See FIG. 21), a compressed stent has alumen that a standard guidewire 201 can freely pass through. This allowsimproved access. When ready, the guidewire 201 can be withdrawn andreplaced with the push wire 200 or the guidewire 201 can have aproximally placed pushing ring 202 that accomplishes the ejection of thepseudo-braided device from the delivery catheter 102.

Upon advancing the delivery catheter 102 to a repair site 104, thepseudo-braided device is deployed from a distal end 106 of the deliverycatheter 102 (FIG. 20). It is contemplated that any number ofconventional means may be employed to eject the pseudo-braided devicefrom the delivery catheter 102, including but not limited to a pusherdevice (not shown) configured coaxially within the delivery catheter 102which operates to engage a proximal end 58 of the pseudo-braided device50 while withdrawing the delivery catheter 102 proximally.

As stated, the pseudo-braided device 50 of the present invention is alsoparticularly suited to operate as an aneurysm cover. As shown in thefigures, the pseudo-braided device 50 can be deployed to overlay anopening 108 to an aneurysm 110 formed in a sidewall of a vessel. Bybeing so positioned, the pseudo-braided device 50 can redirect flow fromentering the aneurysm, become covered with endothelium cells and sealoff the opening into the aneurysm, or retain embolic coils 112 or otherthrombus producing materials inserted in the aneurysm sack 110. It is tobe noted that it is preferred to implace the pseudo-braided device 50prior to embolic material as the same prevents prolapse of material intothe parent vessel.

Using similar methods, the pseudo-braided device 50 of the presentinvention could additionally be employed to repair thrombotic orartherotic stenoses 14 found in a blood vessel 100 (See FIGS. 22 and23). Due to its high expansion ratio and enhanced radial strength (i.e.,hoop strength), the pseudo-braided device 50 can be deployed across thestenosis 114 and be allowed to self-expand to thereby press thethrombotic or artherotic material forming the stenoses against the wallsof the vessel 100. By doing so, the pseudo-braided device operates tohold open and enlarge the vessel 100 at the repair site.

By reconfiguring the basic structure of the pseudo-braided device 50, aspreviously mentioned, the advantages provided by the present inventioncan be used to address other maladies effecting vessels. Morespecifically, the pseudo-braided device 50 can be reconfigured as anembolic protection device 120. With reference to FIGS. 24 and 25, asuperior end portion 122 of the contemplated embolic protection devicescan be necked down so as to form a generally conical profile. Suchnecking could be accomplished by way of altering the manufacturingprocess or the superior end 122 of the pseudo-braided structure cansimply be restrained to a relatively smaller cross-sectional profile byway of adhesion or mechanical devices. It is contemplated that thesuperior end 122 of the embolic protection device 120 be affixed byconventional means to an elongate member 124 that is positionable withina delivery catheter similar to that depicted in FIGS. 19-23. Theinferior end 126 of the embolic protection device 120, in its expandedform, provides a generally circular, cross-sectional profile, openingfor receiving blood flow.

In one embodiment of the embolic protection device 120 (FIG. 25), aplurality of proximally extending filaments or wire loops 128 are routedabout portions of the filament defining the inferior end 126 of theembolic protection device 120. Proximal ends 129 of the loops can beaffixed to a collar that is intended to slide along the elongate member124. Independent control of the collar is also contemplated such that aseparate actuator (not shown) which extends to the operator can besupplied to manipulate the position of the collar along the elongatemember 124. In either case, the loops 128 are provided in the eventadditional control of the opening and closing of the embolic protectiondevice 120 is desired.

Upon advancing the embolic protection device 122 to a desirable locationwithin a patient's vasculature, the elongate member 124 is heldstationary while the delivery catheter (not shown) is withdrawnproximally. The inferior end portion 26 and a tubular midsection 130 ofthe embolic protection device 122 are then permitted to self-expandagainst the walls of the vessel into which the device is deployed. Thefully opened embolic protection device 120 permits blood to flow intoits interior and through its pseudo-braided walls but acts as a barrierto emboli passing through the blood. That is, emboli entering theembolic protection device 120 are captured by its pseudo-braidedstructure. The captured emboli can thereafter be removed from thepatient's vasculature when the embolic protection device 120 is removedor other conventional means such as suction devices can be employed toremove the emboli.

Turning now to FIGS. 26-28, there are shown various embodiments of thepresent invention configured as thrombectomy devices 148. Suchthrombectomy devices 148 can be advanced and deployed within a patient'svasculature using the delivery catheter depicted in FIGS. 19-23. Withspecific reference to FIG. 26, the pseudo-braided device of the presentinvention can be attached at its ends 140, 142 by way of collars 144 toan elongate member 146 to thereby form one embodiment of a thrombectomydevice 148. Upon deployment and expansion within a target vessel, thethrombectomy device assembly 148 provides a mid-section 150 that iswell-suited for engaging and, upon rotation of the device, shearingthrombus from a vessel wall. In order to facilitate self-expansion, onecollar 144 is permitted to slide along the elongate member 146, whilethe other collar is longitudinally fixed thereto.

As shown in FIGS. 27 and 28, the thrombectomy devices 148 may alsoembody pseudo-braided portions of varied density. For example, the moredensely pseudo-braided midsection 152 of the device depicted in FIG. 27is particularly suited for accomplishing the thrombectomy whereas itsless densely pseudo-braided superior end portion 154 is intended forcapture of emboli. The thrombectomy device 148 of FIG. 28 embodies aless densely pseudo-braided midsection contemplated for macerating athrombus adhering to a blood vessel wall whereas its superior endportion 160, being more densely pseudo-braided, is configured forremoval and capture of emboli.

The pseudo-braided device 50 of the present invention can also be closedat each of its ends to form an expandable spherical shape that is suitedas an embolic therapy device 170. With reference to FIG. 29, such anembolic therapy device can be advanced within a vessel using a deliverycatheter 102. The embolic therapy device 170 can then be deployed withinan aneurysm sack 110 and permitted to self-expand to thereby facilitatethrombus formation. A conventional releasable connection 172 to anelongate delivery assembly sub-component 174 is contemplated so that theembolic therapy device 170 can remain in the aneurysm 110 when thedelivery assembly is removed from the patient.

In view of the foregoing, it is clear that the pseudo-braided device ofthe present invention is useful in numerous of applications. Moreover,due to its high expansion ratio and flexibility, the pseudo-braideddevice of the present invention can be employed to repair very distal aswell as tortuous portions of a patient's vasculature.

It will be apparent from the foregoing that, while particular forms ofthe invention have been illustrated and described, various modificationscan be made without departing from the spirit and scope of theinvention. Accordingly, it is not intended that the invention belimited, except as by the appended claims.

What is claimed is:
 1. A method involving employing a device for use in embolic therapy within vasculature having an aneurysm sac, comprising: gaining access to vasculature; placing within an aneurysm sac a device including an elongate filament configured into a pseudo-braided pattern and formed to define a generally tubular body with a first end and a second end; and configuring the body to facilitate thrombus formation within the aneurysm sac, said first and second ends each being defined by a plurality of endless reversals of direction of said filament.
 2. The method of claim 1, the device further comprising at least one more elongate filament interlaced in the pseudo-braided pattern.
 3. The method of claim 1, wherein at least one of said plurality of reversals embody loops having a variable radius of curvature.
 4. The method of claim 1, wherein said pseudo-braided pattern is uniform along a length of said tubular body.
 5. The method of claim 1, wherein said pseudo-braided pattern is non-uniform along a length of said tubular body.
 6. The method of claim 1, wherein said filament is undulated between crossing points.
 7. The method of claim 1, wherein said filament includes a first end and a second end of said filament, said first and second ends being joined together by epoxy.
 8. The method of claim 1, wherein said filament includes a first end and a second end of said filament, said first and second ends being joined in a middle portion of the device.
 9. The method of claim 1, wherein said filament includes a first end and a second end of said filament, said first and second ends being joined at an end of the device.
 10. The method of claim 1, wherein said filament is made from a tube.
 11. The method of claim 1, wherein said filament has a variable cross-sectional profile.
 12. The method of claim 1, wherein said plurality of endless reversals of direction function to enhance hoop strength of said device at said first and second ends thereof.
 13. The method of claim 1, wherein said device can be reduced to less than 10 percent of its expanded diameter.
 14. The method of claim 1, wherein said device can be delivered into a patient's vasculature by a microcatheter.
 15. The method of claim 1, wherein said device is self-expanding.
 16. A method involving employing a device for use in embolic therapy within vasculature having an aneurysm sac, comprising: gaining access to vasculature; placing a device including an elongate filament configured into a pseudo-braided pattern and formed to define a generally spherical body within a delivery microcatheter, said generally spherical body formed by a generally tubular body having first and second ends that are collapsed upon themselves, said first and second ends each comprising a plurality of endless reversals of direction of said filament the spherical body shaped to facilitate thrombus formation within the aneurysm sac, the delivery microcatheter releasably connected to said spherical body; placing the delivery microcatheter within vasculature; and deploying the device to facilitate thrombus formation within an aneurysm sac.
 17. The device of claim 16, wherein said spherical body is self-expanding. 